Invisible Green
John Thomas Sladek
Invisible Green
Age Rating, Reading Level & Content Guide
A Thackeray Phin Mystery
by John Thomas Sladek
The text is written at a 4th grade reading level, the subject matter is intended for middle graders (ages 9–12), and the content is mild with minimal sensitive material.
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About This Book
The Unravellers race through foggy London streets, hearts pounding as they chase down a shadowy figure connected to three mysterious murders. Clues slip through their fingers, and every alley hides a secret. Suddenly, a chilling discovery stops them cold—what will they uncover next?
Quick Assessment
Invisible Green follows a group of young British detective story enthusiasts who band together to solve a series of murders. Suitable for middle-grade readers, the book explores mystery and problem-solving without graphic content, making it appropriate for ages 9-12. Parents should note the presence of crime and suspense elements typical of detective fiction.
Why we rated Invisible Green 9LE
Invisible Green is written at a Level 4-5 reading level across 186 pages. Strong independent readers around grade 5.5 can typically handle this book on their own; with parent or teacher support, Invisible Green works for readers up to grade 6.5.
We rate Invisible Green as 9LE ("Light — Emotional") because the content sits in the "Mild" range — mild conflict — the kind a child encounters in normal play and sibling life. Across our four dimensions (emotional, physical, social, thematic) the book reads as evenly mild; no single dimension stands out as a concern.
No specific content flags were raised by community reviewers, which is consistent with the mild intensity score.
Thematically, Invisible Green explores mystery, friendship, and adventure — these threads give the book room to mean different things to different readers.
Good fit for
- ✓ Children in the Ages 9-12 range — the maturity and attention span match the story's pacing.
- ✓ Kids drawn to stories about mystery, friendship, adventure.
Maybe not for
- ! Readers looking for something heavier — this is a gentle, low-stakes story by design.
For Parents
Content Intensity
9LE — Light — EmotionalLight conflict or tension. Mild peril resolved quickly.
Was our "Mild" content intensity rating accurate for this book?
Reading Insights
Hook Factor
3/10A steady, thoughtful read that rewards patient readers.
Discussion Potential
1/10A lighter read — great for independent enjoyment.
Book DNA
Multi-dimensional content fingerprint
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Details
Book Length
- ISBN
- 080275404X
- Pages
- 186
- Publisher
- Walker
- Published
- 1979
- Type
- Fiction